Thermo-stability and aging performance of modified asphalt with crumb rubber activated by microwave and TOR

Highlights: • Microwave treatment on crumb rubber (CR) degrades the ability of resistance to aging for CR modified asphalt. • Both microwave and TOR benefit to the low temperature behavior for the aged residue. • TOR has an edge over microwave treatment to improve compatibility and stability for CR modified asphalt. • TOR benefits to stability due to chemical reaction, which is verified by decreased intensity of peak at 966 cm^{− 1} in FTIR. More effective approaches need to be developed for solving the aging and thermal stability problems of crumb rubber modified asphalt (CRMA). This paper focused on microwave and trans-polyoctenamer (TOR). Therefore, various CRMA were prepared by crumb rubber (CR), microwave irradiated CR, TOR and base asphalt. The samples were subjected to thin film oven test (TFOT), pressure aging vessel (PAV) and high temperature storage tests. The effects of microwave and TOR were evaluated by rheological, FTIR and SEM tests. The results showed that microwave activated CR increases the risk of fatigue cracking caused by hardening effect of aging but endows the aged residue with stronger resistance to thermal cracking. These results attribute to the degradation and de-vulcanization effect of microwave on CR (verified by FTIR). TOR activated CRMA displayed a more obvious hardening effect and the improved low temperature creep behavior after aging. TOR improves the compatibility and storage stability of CRMA. Double bonds in TOR participate in chemical reaction and benefit to stability, which are verified by the decreased intensity of peak at 966 cm^{− 1}. However, microwave treatment on CR has negative effect on stability of CRMA. Thermal stability was further verified by steady flow method.